Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [login]

the process of logging in: from the login prompt, through user authentication, to session startup

289
votes
5answers
158k views

Difference between Login Shell and Non-Login Shell?

I understand the basic difference between an interactive shell and a non-interactive shell. But what exactly differentiates a login shell from a non-login shell? Can you give examples for uses of a ...
30
votes
3answers
5k views

What's the best distro/shell-agnostic way to set environment variables?

The question says it all. I currently use Arch Linux and the zsh, but I'd like a solution that (at minimum) works both on VTs and in xterms and also (hopefully, preferably) will continue to work if I ...
86
votes
3answers
380k views

SSH login with clear text password as a parameter? [duplicate]

I need to login to a user that I've created on a remote host running Ubuntu. I can't use an ssh key because the ssh login will happen from a bash script ran within a server that I won't have access to ...
119
votes
8answers
27k views

Which is the safest way to get root privileges: sudo, su or login?

I would like to have the root account in safety even if my unprivileged user is compromised. On Ubuntu you can only use sudo for "security reasons" by default. However I am not sure it is any safer ...
31
votes
5answers
67k views

Why doesn't my ~/.bash_profile work?

I'm using Linux Mint. My login shell (cat /etc/passwd | grep myUserName) is bash. After I start my graphical desktop environment and run a terminal emulator from it, I can see that .bash_profile is ...
159
votes
8answers
193k views

What's the difference between /sbin/nologin and /bin/false

Technically, unless pam is set up to check your shell with pam_shells neither of these can actually prevent your login, if you're not on the shell. On my system they are even different sizes, so I ...
52
votes
6answers
108k views

Disable user shell for security reasons

We have several user accounts that we create for automated tasks that require fine-grained permissions, such as file transfer across systems, monitoring, etc. How do we lock down these user accounts ...
32
votes
2answers
19k views

Do you need a shell for SCP?

I'm allowing a friend a local account on my machine, exclusively for SCP. Can I specify his account's shell as /bin/true, or in any other way limit the account, while still allowing SCP?
50
votes
6answers
66k views

Making zsh default shell without root access

I am using my school's computers and would like to use zsh instead of bash. I'd like to make it the default shell, but I cannot run a command such as $ chsh -s $(which zsh) because I don't have admin ...
37
votes
5answers
35k views

how can I use bash as my login shell when my sysadmin refuses to let me change it

The unix sysadmin where I'm working is reluctant to give me access to change my login shell from ksh to bash. He has given various excuses, the funniest being that since they write all their scripts ...
12
votes
3answers
7k views

Creating a UNIX account which only executes one command

Is there a way to create a user account in Solaris which allows the users to run one command only? No login shell or anything else. I could possibly do it with /usr/bin/false in /etc/passwd and just ...
13
votes
4answers
23k views

What are the different ways that a message can be displayed to a bash shell after a user logs in?

I have a CentOS 5.7 VPS using bash as its shell that displays a branded greeting immediately after logging in via SSH. I've been trying to modify it, but can't seem to find where it is in the usual ...
23
votes
3answers
60k views

Execute a command on user logon

In Linux desktop system, I want to execute a command when the user logs in. After reading some other posts, I tried to insert the command in ~/.bashrc but unsuccessfully. Moreover, the system uses a ...
1
vote
3answers
8k views

startx autologin does not run in /etc/inittab in after Debian Jessie update

I installed a minimal Debian system (stable) without GUI, switched to testing/jessie to be able to get the Cinnamon desktop, but X didn't start on boot. If I log in as myself at the CLI, I can type ...
60
votes
4answers
73k views

What is “.xsession” for?

What is the purpose of the .xsession file in the home folder? What should be put in there? The desktop environments don't use that file and for the X startup from the tty there is .xinitrc.
32
votes
2answers
14k views

How does one change the delay that occurs after entering an incorrect password?

After entering an incorrect password at a login prompt, there s an approximately 3-second delay. How can I change that on a Linux system with PAM?
16
votes
10answers
2k views

Concern about logging in as root overrated?

For personal linux on my personal notebooks, I've usually set my environment to autologin as root even under X or lower runlevels. I've found my workflow is very pleasant and fast, without any ...
13
votes
4answers
31k views

How do I configure the GNOME gdm login screen?

I recently installed Arch Linux and have it mostly set up. With many other Linux distributions, there is a tool that is used to configure the look and feel of the login screen. I would like to change ...
85
votes
7answers
169k views

Disable a user's login without disabling the account

Let's say I create a user named "bogus" using the adduser command. How can I make sure this user will NOT be a viable login option, without disabling the account. In short, I want the account to be ...
73
votes
8answers
66k views

Does /usr/sbin/nologin as a login shell serve a security purpose?

In my /etc/passwd file, I can see that the www-data user used by Apache, as well as all sorts of system users, have either /usr/sbin/nologin or /bin/false as their login shell. For example, here is a ...
30
votes
6answers
24k views

Is there any reason why I get ^[[A when I press up arrow at the console login screen?

Whenever I'm at the console login, I press up arrow intentionally to see the previously typed commands. But I see this ^[[A. But when I press Ctrl Alt Print Screen Scroll Lock Pause Break Page Up ...
17
votes
3answers
76k views

I Can't login as root with su command, but I can with SSH

How is it possible that I cannot log in as root by su root or su (I get incorrect password error), but I can log in by ssh root@localhost or ssh root@my_local_IP with the same password? I'm using ...
13
votes
3answers
5k views

Why won't my xmodmap command run on startup/login?

I want to run this command every time I log in (or every time I start up, if that doesn't work): xmodmap -e 'keysym Delete = Menu' -e 'keysym Menu = Delete' I've tried many things. I put the command ...
3
votes
2answers
577 views

Why we can not see a single hyphen from $0 on a login shell invoked with `--login` option?

man bash says, A login shell is one whose first character of argument zero is a -, or one started with the --login option. When we invoke a terminal such as mintty - on Cygwin, we can see a ...
15
votes
7answers
5k views

Is it bad practice to set root's shell to something other than the default?

Once a friend of mine (who is an experienced Unix/Linux user) told me that setting root's shell to something other than sh (i.e bash or zsh) might create problems, because some script might assume ...
457
votes
10answers
1.9m views

How to switch between users on one terminal?

I'd like to log in as a different user without logging out of the current one (on the same terminal). How do I do that?
45
votes
2answers
31k views

Difference between .xinitrc, .xsession and .xsessionrc

I found three configuration files. .xinitrc .xsession .xsessionrc I know that the first one is for using startx and the second and third are used when using a display manager. But what is the ...
8
votes
1answer
90k views

How can I create an SFTP user in CentOS?

I'd like to give temporary SFTP access to a support guy. How do I create an SFTP user? And how can I delete it once the job is done? Also, how do I specify a home directory for them? Can I prevent ...
14
votes
2answers
63k views

Error message id: cannot find name for group ID after logging in

BACKGROUND Trevor logs into his account on ssh://foobar.university.edu as one of the developers on the box, and he gets the message: id: cannot find name for group ID 131 Trevor then checks this ...
26
votes
2answers
56k views

How do I force a user to change a password at the first time login using ssh?

I'm trying to force a newly created user to change a password at the first time login using ssh. For security reasons I want to give him a secure password until he logs in for the first time. I did ...
20
votes
1answer
2k views

WHY a **login** shell over a **non-login** shell?

I have a basic understanding of dotfiles in *nix system. But I am still quite confused about this Difference between Login Shell and Non-Login Shell? A bunch of different answers (including multiple ...
9
votes
3answers
2k views

login and su internals

I am trying to understand how user permissions work in Linux. The kernel boots and starts init as root, right? Init then runs startup scripts and runs getty (agetty), again as root. Agetty just reads ...
2
votes
3answers
12k views

Automatically Login on Debian 9.2.1 Command Line

I just installed Debian 9.2.1 on an old laptop as a cheap server. The computer is not physically accessed by anyone other than myself, so I would like to automatically login upon startup so that if I ...
8
votes
3answers
23k views

Can a command be executed over ssh with a nologin user?

If a user has loginShell=/sbin/nologin is it still possible to ssh user@machine [command] assuming that the user has proper ssh keys in its home directory that can be used to authenticate? My goal ...
6
votes
3answers
19k views

How do I enable auto-login in Mint 18?

Mint 18.2 64b Cinnamon 3.4.3 This is running in a VM on my machine so I'm not worried about login security. I've been looking around on the Mint forums and only found a lot of threads about ...
1
vote
3answers
75 views

How to tell what method was used to log in (Password vs. Keyfile) from the bashrc

Is there a way how you can check what auth method the user which just logged in to an account were using? I like to print out a warning after login if someone is using a password instead of a keyfile....
37
votes
5answers
33k views

How to remove “You have mail” welcome message

When I open up my terminal it says "you have mail", anyone has any idea of why? I am running OS X, but since it too is based on Unix and relies on files such as bashrc, bash_profile etc. I thought ...
10
votes
3answers
27k views

How to run commands automatically on gnome-terminal after log-in?

After each login, there's certain commands that I run on specific tabs of gnome-terminal. This is a tedious process, so can this be done automatically?
15
votes
2answers
82k views

How to know when and which user logged into the system under Mac OS X? Last is not enough!

In Mac OS X, if I don't touch it for a while, it will lock the screen and one must use password to unlock it, but this kind of log in is not recorded by last command. I want to know if anybody tried ...
8
votes
1answer
18k views

Changing the default shell without chsh or administrator privileges

I saw the following snippet in this thread: How to change from csh to bash as default shell sleep 2 if (-x /usr/local/bin/bash) then exec /bin/sh -c '. ~/.profile; exec /usr/local/bin/bash' endif ...
5
votes
2answers
3k views

Changing tmux .bash_profile behavior

I have a script in my .bash_profile that prompts for X sessions to boot. When I launch tmux, I get this prompt that I had only intended for the TTY login. Is there something I can put in ....
10
votes
1answer
2k views

Is there a Bash file that will be always sourced in interactive mode no matter if it is login or non-login?

As far as I know, the interactive shells may be login or not login, and the start up files for them are different. If interactive + login shell → /etc/profile then the first readable of ~/....
8
votes
3answers
7k views

How to execute a script on gdm login automatically for all users?

What file should I modify to execute some instructions when any user logs in through gdm? I tried /etc/bashrc but that is executed ony when starting bash (and each time an xterm is open). I'd like to ...
7
votes
2answers
5k views

How to permanently disable root-password prompt for recovery mode, RHEL7

Note: I asked a similar quesiton concerning version 6 of these bundles here. Note that 7 uses systemd and may have a different implementation In the rare cases that a RHEL or CentOS 7 system is ...
7
votes
3answers
24k views

How to limit the number of active logins per user?

How can I limit the number of active logins per user? I've seen this on various servers before, and I was wondering how I could set this up myself. Perhaps in those cases, this was accomplished by ...
12
votes
3answers
16k views

Is “/etc/issue” common for all Linux distributions?

I'm trying to Create OS detect portable function in bash script, So I just want to know, the file "/etc/issue" is common for all Linux Flavors ?
8
votes
3answers
42k views

What is difference between pbrun and sudo command?

What is difference between pbrun and sudo command? I have seen people executing pbrun sudo su - what this means? I know su -, it will try to switch to root user. What speciality pbrun gives to sudo ...
4
votes
2answers
36k views

Auto running bash script on login

I wanted to make a script which ran automatically on login so I put it into the file ~/bash.profile, but it didn't run. When I put it in bashrc, it ran on opening a terminal. What I was doing in the ...
2
votes
1answer
857 views

upload and dowload the files from server without giving password

I want to download the file from sever by using cron job, so I need to use scp command without giving password by keyword. How do I do so?
1
vote
1answer
15k views

Can't Login to using root user in Kali 2.0 Sana after update

I recently updated my Kali to Sana and I am unable to login as root using my old credentials. I am able to login to the Console with the same username and password but I am not able to login using ...